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Subject[PATCH] blkdev: use an efficient way to check merge flags
Date
A bitwise flag comparison could be done using a more efficient bit-ops way.

Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
---
include/linux/blkdev.h | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1e1fa3f..adfa40a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -655,16 +655,9 @@ static inline bool rq_mergeable(struct request *rq)
static inline bool blk_check_merge_flags(unsigned int flags1,
unsigned int flags2)
{
- if ((flags1 & REQ_DISCARD) != (flags2 & REQ_DISCARD))
- return false;
-
- if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
- return false;
-
- if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME))
- return false;
-
- return true;
+ return (flags1 & (REQ_DISCARD | REQ_SECURE | REQ_WRITE_SAME)) ^
+ (flags2 & (REQ_DISCARD | REQ_SECURE | REQ_WRITE_SAME))
+ == 0;
}

static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
--
1.9.0.GIT


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